Assessment of possibilities of food grade gelatines preparation from chicken skin

Abstract

Chicken skin is a product obtained from the poultry meat processing. This tissue contains mainly fat and proteins, especially collagen. Collagen could be gained from a purification process in which undesirable components, such as fats, pigments and globular proteins, are extracted from the skin. Purified collagen might be used as a starting material for the preparation of high gel strength gelatines applied in food, pharmaceutical and cosmetic industry. Chicken skins are also suitable for processing into collagen hydrolysates of various molecular weights with different purposes as food and cosmetic additives. The aim of this study was to prepare gelatines from chicken skins. Prior to the extraction, non-collagen parts from chicken skin were removed with 1M NaCl, 0.5% NaOH; fats were removed with mixture of Petroleum Ether and Ethanol (1:1). 5 samples of gelatines were prepared by extraction with hot water after pre-treatment with proteolytic enzyme. Effect of extraction conditions, different extraction temperatures (40-80 degrees C) and fixed extraction time (60 min), on gelatine gel strength and yield of the process, were examined. Yields of extracted gelatines ranged between 42-72%. Gel strengths of prepared gelatine samples were between 252-354 Bloom. What is more, prepared chicken skin gelatines were compared with commercial pork and beef gelatines. Results displayed that prepared chicken skin gelatines have comparable gel strength with commercial gelatines.